摘要
目的应用分子动力学模拟金刚石与Ti在热压扩散过程中的界面原子扩散和TiC生成过程。方法采用改进型嵌入原子势函数(MEAM)描述Ti、C和Ti-C之间的相互作用,将模拟过程分为弛豫、热压和保温3个阶段,模拟出金刚石与Ti界面间的原子扩散带厚度、原子扩散速度和TiC的成键过程。为了验证分子动力学模拟结果,进行了聚晶金刚石与钛箔的热压扩散试验,在聚晶金刚石表面制备了Ti涂层。利用扫描电子显微镜观察聚晶金刚石与Ti涂层之间的界面,并进行EDS分析。利用X射线衍射仪分析聚晶金刚石与Ti界面的物相组成。结果模拟结果显示,在弛豫、热压和保温3个阶段,金刚石与Ti之间的扩散带厚度分别为0.8709、0.8889、2.0565 nm,从弛豫到热压阶段,扩散带厚度增加了2.07%,从热压到保温阶段,扩散带厚度增加了131.35%;C原子均方位移曲线斜率为1.8774×10^(-5),Ti原子的均方位移曲线斜率为1.0167×10^(-5),C原子的均方位移的斜率比Ti原子的均方位移的斜率快84.66%;在弛豫20 ps后,C原子的游离键靠近Ti原子,在100 ps的热压过程中,C原子和Ti原子之间形成少量的Ti-C键,在500 ps的保温过程中,在界面间生成大量的Ti-C键。聚晶金刚石与Ti结合紧密、平整,用EDS测试出聚晶金刚石与Ti界面间的扩散带厚度为5.7μm,在聚晶金刚石与Ti界面的XRD图谱测到了TiC衍射峰。结论在金刚石与Ti的热压扩散过程中,C和Ti原子之间存在明显的原子扩散现象,形成了具有一定厚度的扩散带。在金刚石与Ti的界面区域的原子扩散中,C原子的扩散能力和扩散速度大于Ti原子,并在扩散界面内生成了Ti-C键,金刚石与Ti之间形成了化学结合,有助于提高金刚石表面与Ti涂层的结合强度。
The atomic diffusion and TiC formation process between diamond and Ti during hot pressing diffusion process were simulated with molecular dynamics software.The potentials function of modified embedded atom method(MEAM)was used to describe the interactions between Ti,C and Ti-C.The simulation process was divided into three stages:relaxation,hot pressing and thermal insulation.The thicknesses of the atomic diffusion zone between diamond and Ti,as well as the diffusion speed of atoms and the bonding process of TiC were simulated.A hot pressing diffusion experiment of polycrystalline diamond and titanium foil was carried out to verify the results of molecular dynamics simulation.Ti coating was fabricated on surface of polycrystalline diamond with hot pressing diffusion method.A scanning electron microscope was used to observe the interface between polycrystalline diamond and Ti coating,and conducted an EDS analysis of the interface.An X-ray diffractometer was used to analyze the phase compositions of the interface between polycrystalline diamond and Ti.The simulation results show that in the three stages of relaxation,hot pressing and thermal insulation,the thickness of the diffusion zone between diamond and Ti is 0.8709 nm,0.8889 nm and 2.0565 nm,respectively.From the relaxation to the hot pressing stage,the thickness of the diffusion zone between diamond and Ti increases by 2.07%.From the hot pressing to the thermal insulation stage,the thickness of the diffusion zone between diamond and Ti increases by 131.35%.The slope of the mean square displacement curve of C atoms is 1.8774×10^(‒5),and the slope of the mean square displacement curve of Ti atoms is 1.0167×10^(‒5).The slope of the mean square displacement of C atoms is 84.66%faster than that the slope of the mean square displacement of Ti atoms.After a relaxation of 20 ps,the free bonds of C atoms near to Ti atoms.In the process of 100 ps hot pressing,a small amount of Ti-C bonds are formed between C atoms and Ti atoms.During the 500 ps thermal insulation
作者
王贵林
于爱兵
袁建东
李克凡
邹翩
吴森凯
WANG Gui-lin;YU Ai-bing;YUAN Jian-dong;LI Ke-fan;ZOU Pian;WU Sen-kai(School of Mechanical Engineering and Mechanics,Ningbo University,Zhejiang Ningbo 315211,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第8期435-442,共8页
Surface Technology
基金
国家自然科学基金(51875294)。
关键词
热压扩散
分子动力学
金刚石
TI
模拟
hot pressing diffusion
molecular dynamics
diamond
Ti
simulation
